Effects of Dissolved Oxygen Concentration in Electrolyte Film on Atmospheric Corrosion of Carbon Steel

Abstract

Steel is used for infrastructures such as bridges due to its superior mechanical properties as well as low cost. However, atmospheric corrosion of steel causes the deterioration of strength of the steel. As corrosion rate of steel in atmospheric environment strongly depends on the oxygen reduction reaction on rusts of the steel as well as the reduction of the rusts, effects of structure and properties of rust have been examined. In addition, as atmospheric corrosion proceeds under an electrolyte film, the oxygen reduction rate is not necessarily diffusion-limited, that is, the corrosion behavior is reported to be different form that in bulk aqueous electrolyte. Furthermore, steels used for bridges are used for the most of their life time with the presence of rust layer on the steels. Therefore, investigations on the corrosion behavior of rusted steel under an electrolyte film are required to assess the corrosion life time of bridges. The present work aims at revealing the dissolved oxygen concentration in rust layers under an electrolyte film by simultaneous measurements of electrochemical parameters and the dissolved oxygen concentration in an electrolyte film on rusted steel.